The Epidemiology Project of the UC Davis Center for Children's Environmental Health (CCEH), will, in the second funding period, build upon our discovery of immunologicand molecular biomarkers specific to children with autism found in 2-5 year olds enrolled in the CHARGE (Childhood Autism Risks from Genetics and Environment) Study. First, newborn blood spots from children in each of three groups (i.e., autism, developmental delay, and general population controls) will be analyzed in Project 2 for a variety of immune biomarkers and in Core 3 (Analytical Chemistry) for metal concentrations. The data obtained from newborn bloodspots, when compared to data we have already collected from the same individuals in early childhood, will provide important information for the period shortly before birth about immune dysfunction and metal exposures or metabolism in children who are later diagnosed with autism. In other words, we will extend our investigation of post-diagnosis differences to the pre-diagnostic period. The hypothesis we will test is that children with autism can be distinguished from those without autism by markers of immune dysregulation (at birth, as well as post-diagnosis) and by prenatal, immunologically relevant events and exposures. Second, in collaboration with Core 3, we will determine if children with and without autism differ with regard to exposures, body burdens, and excretion of xenobiotics, including metals, pesticides and PBOE's. Exposures are based on questionnaire information and environmental databases covering toxic emissions, hazardous air pollutants and pesticide applications. Body burdens are measured in blood or plasma, and excretion is evaluated in hair or urine;these measurements are performed in the Core 3 laboratories. Third, we will test the hypothesis that transcriptional genomic profiles of children with autism differ from those of children without autism. Particular attention will be placed on genes related to biotic and xenobiotic metabolism. Fourth, Projects 1 and 2 in collaboration with the COTC (Core 2) will collect a second set of blood samples from 375 children who enrolled in the CHARGE study in the first project period. This study (CHARGE-BACK) will examine stability overtime in the immune cell markers that were determined when these children were 2- 5 years old. CHARGE-BACK blood samples will provide peripheral immune cells to study how autism alters properties of cell activation, and susceptibility to known immunotoxicants (Project 2 and Core 4). Fifth, Project 1 will launch a new cohort study that tracks 200 women at high risk of giving birth to a child who develops autism, starting from early pregnancy and following the pregnancies and the babies to the age of three years. This new cohort study is called Markers of Autism Risk in Babies - Learning Early Signs (MARBLES). Fieldwork for the MARBLES study will be tightly integrated with the COTC (Core 2) efforts, and the specimens will be evaluated in Cores 3 and 4, and in Project 2. The goal is to determine early predictors of autism, whether they be immunologic, genomic, or environmental.